1. Field of the Invention
This invention relates to the treatment of textile cords for use as tensile reinforcements in elastomeric products, and more particularly, to the treatment of aramid cords for such uses.
2. Description of Related Art
Textile cord has long been used as a tensile reinforcement material for reinforcing various elastomeric products, for example, power transmission belts, conveyor belts, hoses, tires, and the like. In order to serve as a reinforcement, the textile cord typically is embedded in the particular elastomeric material. And, depending on the particular end use of the reinforced elastomer, oftentimes the cord is treated prior to being embedded in the elastomer in order to enhance any of a number of desired properties, for example, cord-to-elastomer adhesion, inhibition of textile-filament degradation, and flexibility.
Various treatments have been proposed for treating aramid cord that is to be used in reinforcing an elastomeric product (i.e., a rubber product). Specifically, one treatment proposes treating the cord with a resorcinol-formalin-rubber latex adhesive (“RFL”) liquid. While the bending performance of cords treated with RFL solutions is good, there is a tendency for cut edges to fray during manufacturing and belt operation. In addition, moisture uptake can be a problem due to incomplete impregnation of the cord due to the evaporation of the water carrier which can lead to voids and untreated areas of cord. Moisture uptake has the potential to lead to dimensional instability in certain types of fibers like aramid. Another approach calls for pretreating the cord with an isocyanate solution or an aqueous based epoxy solution, and then treating the pretreated cord with an RFL liquid. While this methodology tends to improve a cord's resistance to fray, it results in an undesirable reduction in bending fatigue resistance. Epoxy solutions and isocyanate solutions may also lead to unwanted moisture uptake after treatment.